Hydroxymethyltetrahydropyran production

ABSTRACT

PRODUCTION OF 2-HYDROXYMETHYLETETRAHYDOROPYRANS AND 3 - HYDROXYMETHYLTETRAHYDROPYRANS IN HIGH YIELDS IS EFFECTED BY HYDROFORMYLATION OF 3,6 - DIHYDRO - 2- (H)PRYANS IN THE PRESENCE OF CO, HYDROGEN, AND AN OXO CATALYST.

United States Patent Office 3,555,048 HYDROXYMETHYLTETRAHYDROPYRAN PRODUCTION Paul R. Stapp and James D. Allen, Bartlesville, Okla.,

assignors to Phillips Petroleum Company, a corporation of Delaware No Drawing. Filed Nov. 15, 1967, Ser. No. 683,153 Int. Cl. C07d 7/.04

US. Cl. 260-3453 3 Claims ABSTRACT OF THE DISCLOSURE Production of Z-hydroxymethyltetrahydropyrans and 3 hydroxymethyltetrahydropyrans in high yields is effected by hydroformylation of 3,6 dihydro 2 [H]- pyrans in the presence of CO, hydrogen, and an oxo catalyst.

BACKGROUND OF THE INVENTION This invention relates to an improved process for producing 2-hydroxymethyltetrahydropyrans and 3-hydroxymethyltetrahydropyrans by hydroformylation. In accordance with another aspect, this invention relates to a process for converting a 3,6-dihydro-2-[H]-pyran to a high yield of a mixture of a 2-hydroxymethyltetrahydropyran and a 3-hydroxymethyltetrahydropyran by contacting with CO and H in the presence of an oxo catalyst.

Hydroxymethyltetrahydropyrans are useful compounds. For example, Francis and Rudloff, Can. J. Chem, volume 37, pages 972-978 (1959), disclose that 2-hydroxymethyltetrahydropyran can be converted to 1,3,6-hexanetriol and 1,2,6 hexanetriol. U.S. Pat. 2,768,213 discloses that hexanetriols can be employed for many purposes in lieu of glycerine. Particularly, US. Pat. 2,768,213 discloses that 1,2,6-hexanetriol can be converted to C C monocarboxylic esters, which are improved plasticizers for the resinous polymers of polymerizable ethylenic compounds, for example, polyvinyl chloride. Example V of that patent discloses that such esters, particularly the tricaprylate of 1,2,6-hexanetriol, impart unusually good low temperature characteristics to polyvinyl chloride resins. Of course, the products of the instant invention are believed useful for a variety of applications such as solvents, chemical intermediates, polymer precursors, and the like.

The production of 2-hydroxymethyltetrahydropyran by the process of the instant invention constitutes a totally unexpected result and an advance in the art. Falbe and Korte (Chemical Abstracts, volume 61, page 634 [1964]) disclose that 2,3-dihydro-4-[H1-pyran (5,6-dihydro-4- [H]-pyran), CO, and H can be converted to a mixture comprised of 2-hydroxymethyltetrahydropyran and 3- hydroxymethyltetra-hydropyran in the presence of an oxo catalyst (cobalt carbonyl). That reaction might be predicted by one skilled in the hydroforrnylation art since hydrogen is added to one carbon of the double bond and hydroxymethyl is added to the other carbon of the double bond. The conversion of the instant invention is totally unexpected, however; instead of a product comprised of 3-hydroxymethyltetrahydropyran and 4-hydroxymethyltetrahydropyran, a high yield of 2-hydroxymethyltetrahydropyran was obtained. This was a surprising result.

Accordingly, an object of this invention is to provide an improved process for the hydroformylation of 3,6-dihydro-2-[H1-pyrans.

Another object of this invention is to provide a process for producing hydroxymethyltetrahydropyrans, wherein high yields and substantially complete conversions are obtained.

Other aspects, objects, as well as the several advantages of this invention will be apparent to those skilled in the 3,555,048 Patented Jan. 12, 1971 art upon reading the specification and the appended claims.

SUMMARY OF THE INVENTION PREFERRED EMBODIMENTS OF THE INVENTION The reactant dihydropyran that can be used in this invention has the formula R- R R [H H wherein R can be hydrogen and where one and only one R group per molecule can be alkyl, cycloalkyl, or combinations thereof, and can contain to and including about 17 carbon atoms per R group.

Representative examples of 3-6-dihydro-2-[H]-pyrans that can be employed having the formula noted above include 3,6-dihydro-2-[H1-pyran, 2-methyl-3,6-dihydro-2 [H] pyran, 3 heptadecyl-3,6-dihydro-2-[H]-pyran, 4- octyl 3,6 dihydro 2 [H] pyran, 5-cyclohexyl-3,6- dihydro-Z- [H] -pyran, 6-propyl-3 ,6-dihydro-2- [H] -pyran, 2-cyclododecyl-3 ,6-dihydro-2- [H] -pyran, 3- 3-cyclohexyl- 4-ethyl-5-methyloctyl) -3 ,6-dihydro-2- [H] -pyran, 2- [4- 2- ethyl 3 methylcyclopentyl)heptyl]-3,6-dihydro-2-[H]- pyran, 2-( 1-methyl-2-propyl-4-ethyldecyl -3,6-dihydro-2- [H]-pyran, and the like.

The hydroxymethyltetrahydropyrans produced from the dihydropyrans noted above have the formulas:

H R R 0112011 and RL CHzOH H R wherein R can be hydrogen and where one and only one R group per molecule can be alkyl, cycloalkyl, or combinations thereof, and can contain to and including about 17 carbon atoms per R group.

Illustrative and representative hydroxymethyltetrahydropyrans produced according to the invention having the above formula include: 2-hydroxymethyltetrahydropyran, 3 hydroxymethyltetrahydropyran, 3 hydroxymethyl 2 methyltetrahydropyran, 2-hydroxymethyl-3 heptadecyltetrahydropyran, 3 hydroxymethyl 3-heptadecyltetrahydropyran, 3 hydroxymethyl S-cyclohexyltetrahydropyran, 2 hydroxymethyl S-cyclohexyltetrahydropyran, 3 hydroxymethyl 2- [4-(2-ethyl-3-methylcyclopentyl)heptyl] tetrahydropyran, 3-hydroxymethyl-2- (1-methyl-2-propyl-4-ethyldecyl)tetrahydropyran, and the three-hour reaction period. Upon cooling, the product was like. removed and fractionally distilled to yield 16 g. of a The conversion, in accordance With the invention, is mixture comprised of about 75 mole percent 2-hydroxyrepresented by the following: methyltetrahydropyran and about 25 mole percent 3-hy- R H l R R -R H R L H 0x0 catalyst H/ O R H/ O whereinRis defined above. droxymethyltetrahydropyran (B.P. 68-97 F. at 8 mm.

The above hydroformylation reaction can be effected at Hg), as determined by G-LC (gas-liquid chromatogpressures in the range of about 500 p.s.i.g. to about 10,000 raphy). Yield of hydroxymethyltetrahydropyrans was 70 p.s.i.g., preferably in the range of about 2,000 p.s.i.g. to 1 mole percent, based on the 3,6-dihydro-2-[Hl-pyran about 3,000 p.s.i.g. Temperatures in the range of about charged. Conversion of 3,6-dihydro-2-[H]-pyran was de- 250 F. to about 500 F. can be employed, temperatures termined to be 100 percent. in the range of about 350 F. to about 400 F. are pre- Infrared spectra of the product were consistent with ferred. Sufficient reaction time should be employed to expected spectra for a mixture of Z-hydroxymethyltetraeffect the degree of conversion desired, normally we prefer hydropyran and 3-hydroxymethyltetrahydropyran.

to employ reaction times of in the range of about 5 The products of a series of runs, as exemplified by the minutes to about 12 hours, more preferably reaction times run above, were combined and purified. Gas-liquid chroin the range of about 1 to about 4 hours. matography of the purified product determined it to be Carbon monoxide should be employed in a quantity at comprised of about mole percent l t-hydroxymethylleast molarly equivalent initially to the 3,6-dihydro-2-[HJ- 25 tetrahydropyran and about 75 mole percent 2-hydroxy pyran charged. Molar excesses of carbon monoxide are methyltetrahydropyran (chromatographic column was 5 preferred. For example, the molar ratio of 3,6-dihydroft. in. Carbowax 20 M, only two peaks were observed, 2-[H]-pyran compound/carbon monoxide can range from no evidence of impurities was observed). The purified about 0.05 to about 1.0, the preferred ratio is in the range sample was characterized by nuclear magnetic resonance of about 0.1 to about 0.5. The molar ratio of carbon analysis, elemental analysis, and molecular weight determonoxide/hydrogen can be in the range of about 0.5 to mination. NMR data were as expected. Molecular weight about 2. In general, however, molar ratios of carbon calculated for hydroxymethyltetrahydropyran is 116, monoxide/hydrogen should be about 1. molecular weight found was 116. The material was de- A suitable hydroformylation catalyst (oxo catalyst) termined to have 61.7 percent carbon and 10.5 percent should be employed, which can be any conventional hyhydrogen. Elemental composition calculated for hydroxydroformylation catalyst. Examples can include Co (CO) methyltetrahydropyran is 62 percent carbon and 10.4 rhodium oxide, palladium oxide, iridium oxide, ruthenium percent hydrogen. The major peak found with G-LC analoxide, palladium chloride, and the like. Such catalysts ysis was consistent with the peak formed by an authentic should be employed in quantities sufiicient to effect the sample of 2-hydroxymethyltetrahydropyran. The minor hydroformylation conversion Within the times desired. eak. clearly iff f the major p was consistent Such catalysts are generally employed in the range of with 3-hydroxymethyltetrahydropyran.

about 0.001 to about 0.15 part of catalyst per part of This example clearly demonstrates that the products 3,6-dihydro-2-[H]-pyran compound charged. produced from 3,6-dihydro-2-[H] -pyrans according to the Suitable diluents are also preferably employed, A suitprocess of this invention are not those which would be predicted by the teachings of the art. The following repable diluent is any material normally liquid under the resentations of the chemistry involved more clearly show reaction environment which is employed that does not deleteriously affect the said hydroformylation conversion. he un Xpected results. Such diluents can be either polar or nonpolar. Examples Representation I, conversion of 3,6-dihydro-2-[H]- include pentane, hexane, cyclohexane, benzene, naphthapyran according to the process of the instant invention:

lene, dodecane, octane, decane, xylene, toluene, acetone, methyl ethyl ketone, ethanol, 2-propanol, tetrahydropyran,

H H l tetrahydrofuran, methyl isobutyl ketone, ethyl ether, iso- C CO propyl ether, n-butanol, n-hexanol, and the like. If alcohols 1 H C0 M H H o are employed as diluents, higher temperatures, within the Cataly range disclosed, and longer reaction times, within the range disclosed, should preferably be employed. Such H H H H diluents can be employed in quantities sufficient to com- H CHaOH H H prise in the range of about 1 to about 90 weight percent H H- H of the reactor contents. H H Hi CHzOH The hydroxymethyltetrahydropyrans produced by the H H process of this invention can be recovered by any means O 0 known to the art such as crystallization, solvent extraction, Representation I, conversion of 2,3-dihydro-4-[H]- and the u pyran according to the prior art disclosure:

Conventional equlpment and conventional techniques including batch, semicontinuous, and continuous opera- H H tions can be employed to effect the process of this invention. C02: Oh SPECIFIC EXAMPLE C0 H2 m a a S To a reactor were charged 17 g. (0.2 mole) of 3,6- y dihydro-2-[H]-pyran and 50 ml. of cyclohexane. Syn- H H H H thesis gas (CO:H 1:1 ratio) was pressured to 2,200 H CHZOH H p.s.i.g. Temperature of the reactor contents was 60 F., and was then raised to 260 F. Five ml. of a mixture comprised of 0.39 g. cobalt carbonyl catalyst and benzene was added. The temperature was raised to 390 F. for a We claim:

1. A process for the production of hydroxyrnethyltetrahydropyrans which comprises reacting 3,6-dihydro- 2-[H]-pyran with CO and H in the presence of cobalt carbonyl, to produce a mixture of 2-hydroxymethyltetrahydropyran and 3-hydroxymethyltetrahydropyran, said reacting being conducted at a temperature ranging from 250-500 R, an elevated pressure ranging from about 500 p.s.i.g. to about 10,000 p.s.i.g., and for a period of time of 5 minutes to 12 hours.

2. A process according to claim 1 wherein said reacting is conducted at a temperature in the range 350-400 F., at elevated pressure in the range between 2,0003,000 p.s.i.g., and for a period of time in the range of about 1 to about 4 hours.

3. A process according to claim 1 wherein the reacting is conducted in a reaction diluent.

References Cited 5 UNITED STATES PATENTS 3,168,575 2/1965 Prosser 260614X 3,257,415 6/ 1966 OGrady et al 260-3405 OTHER REFERENCES 15 NORMA S. MILESTONE, Primary Examiner 

